This first picture is a comparison of the three MM devices that I have. I affectionately refer to them as the three amigos.

The one on the right is my first jailbird. I sized it based on the CB6000S that I was going to get to replace my CB3000. It is 1 3/6" diameter and 2 1/2" long.
The one on the left is my new jailbird. It is 1 1/8" diameter and 2 1/4" long.
The one in the middle is the Pet Trap. It has two diameters, the opening is 1 1/8" diameter and the end with the bars is 1 1/4" diameter. The length is 2".
This picture actually does a pretty good job representing the relative sizes of these three devices. It is hard to tell but the back edge of the bottom of the rings are all in a straight line. The inside diameter of the Pet Trap is actually bigger than the jailbird on the left, 1.14" v 1.10" even though it doesn't look like it. It doesn't look like it when holding them either. The Pet Trap seems really, really small even though it isn't really. The thinness of the material contributes to this. The fact that the bars on the jailbird are out further than the inside diameter of the rings also contributes to its size.
This second picture is of the Pet Trap assembled with the base ring. It shows the difference in the two diameters a little better.

You can see that there is less access on this device. That is part of what is contributing to the difficulty I am having getting everything 'working' so to speak. To be fair I haven't spent much time with it yet, only about 36 hours last weekend. The biggest problem is all the skin on the underside of the penis. There just isn't much room for it all. It has been pushing in to the bottom of the bars which points the end of the penis up a little. It actually works ok because I can pee out the upper opening in the bars and it is actually easier to see to align everything. The problem is that the skin protrudes in weird ways at the bottom of the bars. Some time playing with it should help figure everything out.
As you can probably imagine from the pictures it practically disappears under clothing. There just isn't much there. With the screw lock there is only a miner protrusion at the end of the locking pin. That would even be less except that I did get the anti-pullout pins. I know others haven't cared for them but I like having them even if I don't wear them all the time.
This last picture is one I shared elsewhere showing the extra hole I had put in for an authentication tag.

Not much to say about this. It should be effective but I haven't tried wearing it with a tag yet to see if it gets in the way or anything. I will worry about this once I have been able to wear it for a while.
I am sure I will have more to add as time goes on. In the mean time if you have any questions feel free to ask.
-A